SQLite

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.175 2007/10/12 19:11:55 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include <stdlib.h>
#include <assert.h>
#include "vdbeInt.h"

){
  const unsigned char *z;
  const unsigned char *z2;
  int len;
  int p0type;
  i64 p1, p2;

  assert( argc==3 || argc==2 );
  p0type = sqlite3_value_type(argv[0]);
  if( p0type==SQLITE_BLOB ){
    len = sqlite3_value_bytes(argv[0]);
    z = sqlite3_value_blob(argv[0]);
    if( z==0 ) return;
    assert( len==sqlite3_value_bytes(argv[0]) );
  }else{
    z = sqlite3_value_text(argv[0]);
    if( z==0 ) return;
    len = 0;
    for(z2=z; *z2; len++){
      SQLITE_SKIP_UTF8(z2);
    }
  }
  p1 = sqlite3_value_int(argv[1]);
  if( argc==3 ){
    p2 = sqlite3_value_int(argv[2]);
  }else{
    p2 = SQLITE_MAX_LENGTH;
  }
  if( p1<0 ){
    p1 += len;
    if( p1<0 ){
      p2 += p1;
      p1 = 0;
    }
  }else if( p1>0 ){

  } aFuncs[] = {
    { "min",               -1, 0, SQLITE_UTF8,    1, minmaxFunc },
    { "min",                0, 0, SQLITE_UTF8,    1, 0          },
    { "max",               -1, 1, SQLITE_UTF8,    1, minmaxFunc },
    { "max",                0, 1, SQLITE_UTF8,    1, 0          },
    { "typeof",             1, 0, SQLITE_UTF8,    0, typeofFunc },
    { "length",             1, 0, SQLITE_UTF8,    0, lengthFunc },
    { "substr",             2, 0, SQLITE_UTF8,    0, substrFunc },
    { "substr",             3, 0, SQLITE_UTF8,    0, substrFunc },
    { "abs",                1, 0, SQLITE_UTF8,    0, absFunc    },
    { "round",              1, 0, SQLITE_UTF8,    0, roundFunc  },
    { "round",              2, 0, SQLITE_UTF8,    0, roundFunc  },
    { "upper",              1, 0, SQLITE_UTF8,    0, upperFunc  },
    { "lower",              1, 0, SQLITE_UTF8,    0, lowerFunc  },
    { "coalesce",          -1, 0, SQLITE_UTF8,    0, ifnullFunc },

# 2007 May 14
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the built-in SUBSTR() functions.
#
# $Id: substr.test,v 1.3 2007/10/12 19:11:55 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !tclvar {
  finish_test
  return

subblob-test 4.1 61E188B462E28D8563E3919663 1 1 61
subblob-test 4.2 61E188B462E28D8563E3919663 2 1 E1
subblob-test 4.3 61E188B462E28D8563E3919663 1 2 61E1
subblob-test 4.4 61E188B462E28D8563E3919663 -2 1 96
subblob-test 4.5 61E188B462E28D8563E3919663 -5 4 63E39196
subblob-test 4.6 61E188B462E28D8563E3919663 -100 98 61E188B462E28D8563E391 

# Two-argument SUBSTR
#
proc substr-2-test {id string idx result} {
  db eval {
    DELETE FROM t1;
    INSERT INTO t1(t) VALUES($string)
  }
  do_test substr-$id.1 [subst {
    execsql {
      SELECT substr(t, $idx) FROM t1
    }
  }] [list $result]
  set qstr '[string map {' ''} $string]'
  do_test substr-$id.2 [subst {
    execsql {
      SELECT substr($qstr, $idx)
    }
  }] [list $result]
}
substr-2-test 5.1 abcdefghijklmnop 5 efghijklmnop
substr-2-test 5.2 abcdef -5 bcdef

finish_test

#
# Run this Tcl script to generate the lang-*.html files.
#
set rcsid {$Id: lang.tcl,v 1.137 2007/10/12 19:11:55 drh Exp $}
source common.tcl

if {[llength $argv]>0} {
  set outputdir [lindex $argv 0]
} else {
  set outputdir ""
}

<tr>
<td valign="top" align="right">sqlite_version(*)</td>
<td valign="top">Return the version string for the SQLite library
that is running.  Example:  "2.8.0"</td>
</tr>

<tr>
<td valign="top" align="right">
  substr(<i>X</i>,<i>Y</i>,<i>Z</i>)<br>
  substr(<i>X</i>,<i>Y</i>)</td>
<td valign="top">Return a substring of input string <i>X</i> that begins
with the <i>Y</i>-th character and which is <i>Z</i> characters long.
If <i>Z</i> is omitted then all character through the end of the string
are returned.
The left-most character of <i>X</i> is number 1.  If <i>Y</i> is negative
the the first character of the substring is found by counting from the
right rather than the left.  If <i>X</i> is string
then characters indices refer to actual UTF-8 characters.  If
<i>X</i> is a BLOB then the indices refer to bytes.</td>
</tr>